Camera shutter



L.. HAMMOND CAMERA SHUTTER Aug. 2l, 1945. 2,383,381

Filed 0G12. 28, 1942 2 Sheets-She'et 1 a af' ens 17am/nona Aug. 2l, 1945. 1 HAMMOND 2,383,381

CAMERA SHUTTER Filed Oct. 28, 1942 'z sheets-sneet 2 Patented Aug. 2l, 1945 UNITED STATES PATENT OFFICE CAMERA SHUTTER Laurens Hammond, Chicago, Ill.

Application October 28, 1942, Serial No. 463,641

7 claims.

My invention relates generally to camera shutters, and more particularly to shutter mechanisms for aerial cameras having large lens apertures.

Considerable difficulty has been experienced in' adapting shutter mechanisms for aerial and similar cameras having large objective lenses, which may be in the order of in diameter, because of the extremely high acceleration and deceleration of the parts which is required for obtaining short exposures.

It is therefore an object of my invention to provide an improved shutter mechanism for aerial and similar cameras in which the shutter parts are not rapidly accelerated or decelerated but which, neverthelessy may be utilized to obtain exposures as short as 1/aoo to 1/iono of a second.

A further object is to provide an improved shutter mechanism for cameras having large objective lenses in which the parts which necessarily move at high speed are continuously rotated.

A further object is to provide an improved shutter mechanism for aerial cameras and the like in which the' shutter mechanism may control the operation of the hlm winding mechanism, whereby the operation of these mechanisms may be synchronized and successive exposures made at short intervals.

A further object is to provide an improved shutter mechanism for aerial cameras and the like which is simple in construction and light in weight, which may be economically manufactured, and which will have a long useful life.

Other objects will appear from the following description, reference being had to the accompanying drawings in which:

Figure 1 is a. side elevational view of the improved shutter mechanism applied to an aerial camera which is conventionally illustrated;

Figure 2 is a vertical sectional view of the shutter mechanism taken through the axis of rotation of the shutters and the axis of the trip plunger;

Figure 3 is a plan view of one of the high speed shutters;

Figure 4 is a plan view of one of an intermediate speed shutter;

Figure 5 is a perspective view of the shutter release mechanism taken generally on the line 5 5 of Fig. 2;

Figures 6 and 7 are fragmentary sectional views of the gear trains takenrespectively on the lines 0-3 and 'l-l of Fig. 2;

Figure 8 is a horizontal sectional view of a modied form of shutter trip mechanism; and,

Figure 9 is a sectional view taken on the line 9 9 of Fig. 8.

The invention is illustrated as forming part oi' an aerial camera Iii o! any suitable construction, having a lm winding mechanism l2 forming a part thereof. The shutters are mounted within a case I4 which intersects the lens casing I6 of the camera so that the shutters pass between lenses il and I8.

Five shutters 20, 2i, 22, 23 and 24 are mounted for rotation within the case I4, being driven by gearing contained in housings 26 and 21. Power for driving the shutters is obtained from a suitable motor 28 having a drive shaft 29 connected to a variable speed transmission 30, the speed of which may be adjusted by means of suitable controls 32. The gearing within the housing 26 is driven from the variable speed gearing 30 through a drive shaft 3l. n

The high speed shutter discs 2li, 2| may be identical and of the form shown in Fig. 3, wherein it will be seen that these discs have diametrically opposite sector shaped apertures 36. For the embodiment herein describedr these apertures 36 may be 6.10' in angular width, and since the apertures are diametrically oppositev the discs 20. 2l wiil be in static and dynamic balance.

The diac 22 rotates at intermediate speed and has but one aperture 38, which may be of somewhat greater angular width than the aperture 36, and is illustrated as. having an angular width oi 72. The disc 22 is provided with balancing weights Il) which may be in lthe form of stampings Awelded to thc disc 22 adjacent the aperture 38. In lieu of using one counter weight stamping l0, two similar but thinner stampings may be provided, welded or otherwise suitably secured to the opposite sides of the disc 22. The counter weights 40 are of such mass and shape that the disc 22 is statically and dynamically in balance.

The low speed disc 23 may be identical in shape with the disc 22, but need not be provided with a counter weight, since it operates at a relatively slow speed. The manually controlled disc 24 likewise operates at a slow speed and need not be provided with a baiancing weight, being otherwise similar to the disc Z2.

The apertures 36 are of such angular width that when either of these apertures is in alignment with the lenses i 1, i3, light passage through the latter will be unobstructed.

The general principle of operation of the mechanism is that the discs 20 and 2| rotate at high speed in opposite directions so that twice during each revolution thereof these apertures 26 will be f and I8 only during every fifth time that the apertures 36 are in alignment with the lenses.

The disc 23 rotates at one-fifth of the speed of the disc 22 so that its aperture will be in alignment with the lensesduring only every fifth time that the aperture of the disc 22 is in alignment with the lenses. The disc 24 is normally stationary obscuring the lens I1, but when tripped, as will hereinafter appear, it is rotated at a speed one-fifth that of the disc 23. The disc 24 is therefore the slowest speed disc, and since it is manually tripped is also designated herein as a shutter.

As illustrative of the speeds at which the shutter discs may be rotated and the exposure intervals which may be obtained, the discs 20 and 2| may, for example, be rotated in opposite directions at a speed of 3600 R. P. M., the disc 22 rotated at 1500 R. P. M., the disc 23 rotated at 300 R. P. M., and the disc 24, when tripped, at 60 R. P. M. With the shutter discs rotating at these speeds and provided with apertures of the angular dimensions set forth above, the exposure will be 1/300 of a second, and if the tripping mechanism is maintained in shutter release position, successive exposures will be made at one second intervals. Any suitable mechanism may be used to drive the shutter discs, one such mechanism being shown herein.

The disc 22 is suitably secured to a central shaft 50 mounted for rotation in bearings 5| and 52, the bearing 5| being supported in the housing 21 and the bearing 52 being supported in the housing 26. The housing 21. is suitably secured to a generally circular plate 54 forming the bottom of the shutter casing I4, while the housing 26 is secured to an upper plate 56 of the housing I4, this upper plate having suitable extensions for supporting the motor 28.

The drive shaft 34 is supported by a pair of bearings 58 and 59 carried by the housing 28, and at its inner end has a bevel pinion 60 secured thereto and meshing with a bevel gear 6| rigidly secured to the central shaft 50. 'Ihe disc 22 has a hub 84 which is non-rotatably secured to the shaft 50. (Such parts as are non-rotatable with respect to the shaft upon which they are mounted are indicated as being pinned thereto, although in actual practice other methods of non-rotatably securing these parts to the shaft are utilized.)

The disc 20 has its hub 66 formed integrally with or secured to a sleeve 68 surrounding the shaft 50 and bearing thereon, this sleeve having a pinion 10 secured to its opposite end. As shown in Fig. 7, a pinion 12 is secured to the central shaft 50 and forms the hub for a gear 14. The gear 14 meshes with an idler pinion 18 secured to a stub shaft 18 carried in a bearing 80 which is staked to the wall of the housing 26. The idler pinion 'I6 meshes with a gear 82 and the latter meshes with the pinion 10. Thus, the shutter disc 20 is driven through the following train of gearing-shaft 34, bevel pinion 80, bevel gear 8|, gear 14, idler pinion 16, gear 82, and pinion 10. This is a speed increasing gearing of such ratio that if the shaft 50 rotates at 1500 R. P. M. the disc 20 will rotate at 3600 R. P. M.

The disc 2| has its hub 84 secured to a sleeve 86 bearing on the shaft 50. The sleeve 86 has a and sleeve |34.

gear 88 secured thereto, this gear meshing with a gear secured to a stub shaft 82 rotatable in the bearing 84 secured to the housing 21. Likewise secured to the stub shaft 82 is a pinion 88 which meshes with a gear 88 secured to the central shaft 50. The shutter disc 2| is thus driven thnough the following gear train-shaft 50, gear 88, pinion 36, gears and 88, and sleeve 88. This gearing is arranged to drive the shutter disc 2| at the same speed as the disc 20, namely, 3600 R. P. M., but in a direction opposite to that in which the disc 20 is driven.

The shutter disc 23 is secured to a sleeve |00 which rotates in a bearing |02 secured to the plate 54 and which, at its outer end, has a gear |04 staked thereto. Gear |08 meshes with a pinion |06 staked to a hub |08 and counter shaft |I0. The counter shaft |I0 is mounted for free rotation in bearings III and I|2 secured respectively to the plate 54 and the wall of housing 21. A gear ||4 is staked to the hub |08 and meshes with the gear 98. Thus, the disc 23 is driven through the following train of gearingcenter shaft 50, gear 88, gear ||4, hub |00, pinion |08,

gear |04, and sleeve |00. This gearing is so proportioned that the disc 23 will rotate at a speed of 300 R. P. M. assuming that the shaft 50 is rotating at 1500 R. P. M.

A plunger shaft ||8 is mounted for rotation and longitudinal sliding movement in bearings ||1 and II8, respectively secured to the plate 58 and the wall of housing 28. The upper end of the plunger lshaft |I6 has a push button |20 rotatably secured thereto. This button is forced outwardly by a compression coil spring |22, such outward movement being limited by the engagement of the collar |24 with the bearing III. Rigidly securedto the shaft ||8 is a pinion |28 having a gear |28 staked thereto. The gear |28 meshes with the pinion 12 at all times, while the pinion |26 is adapted, when the button |20 is depressed, to move the plunger shaft I I8 inwardly to engage a gear |30 which is staked to a hub |32, the latter being non-rotatably secured to a sleeve |34. The sleeve |34 is mounted for rotation in a bearing |38 carried by the plate 58 and at its inner end forms the hub for shutter disc 24.

The hub |32 has a. cam disc |38 formed integrally therewith or suitably secured thereto, this disc carrying a cam |40, which is adapted to engage a pivoted follower lever |42 which' is biased for engagement with the cam |40 by a compression spring |44. The follower lever |42 is connected to a Bowden wire |48 which is adapted totrip the illm winding mechanism to cause the latter to wind the film and thereby position the next frame thereof for exposure. The cam disc |38 has a notch |50 formed in the periphery thereof which is adapted freely to receive a locking disc |52 secured to the plunger shaft II8. When the plunger is in the normal position sh'orwn in Fig. 2, the disc |52 is in engagement with the notch |50 and thus prevents rotation of the cam disc |38 and all of the parts which are secured thereto, including the shutter disc 24.

When the button |20 is depressed against th'e force of the spring |22, the locking disc |52 is moved out of the arcuate notch |50 and immediately thereafter the pinion |28 engages the gear |30 to drive the latter. A drive for rotating the shutter disc 24 is thus established through the following train of gearingcenter shaft 50, pinion 12, gear |28, pinion |26, gear |30, hub |32, This gearing is so arranged that, assuming that the shaft 50 rotates at 1500 R. P.

M., the shutter disc 24 will be rotated at60 fR.. P. M.

It is desirable that the pinion |20 engage the gear only when the former is in a predeter-` mined angular position. This is accomplished by providing a movable sto'p lever |00 which is pivotally mounted upon a suitable support |02 and is prevented from rotating counterclockwise l on this support by a lug |04. Clockwise rotation of the lever |00 is permitted against the force of a compression coil spring |00. The disc |02 has a notch |00 which normally passes above the end of the lever |00. one. side of this notch being pref erably provided with a helical cam face which is cooperable withl a complementally shaped cam face |12 formed at the end of the lever |00. By virtue of this arrangement, the pinion will always be in a predetermined orientation the instant it meshes with the gear |30. since it will not be possible to depress the push button |20 until the notch' |00 is in line with the end of the lever |00. As soon as this occurs, the disc |52 of an arm |09 of the lever |04 and a stop pin |90 projecting from the plate |30a. The plate |30a is frictionally constrained to rotate with the plate |00 by virtue of a frictional connection including a spring washer |92. l

A release knob |90 is secured to the end of a release bar |91 which is suitably guided in the casing 20 and a bracket |94, and is normally held in the position shown in Fig. 8 by a compression coil spring |90. The inner end of the release bar |91 is adapted to engage the third arm |99 of the lever |04. 'I'he friction afforded by the washers |92 is adequately sufficient to maintain thelever will move downwardly and such downward move- The notch so m the use m 1s so positioned relative to the aperture in the disc 24 'that shortly after button |20 is depressed and the disc 24 thus engaged with' the drive gearing. the aperture in the disc 24 will traverse the lens opening and thus, at theinstant the apertures of the other discs are likewise in alignment with the lens openings. expose the film. After the cam disc |00 is rotated through approximately 180, its cam |40 will engage the follower lever |42 and trip the film winding mechanism 2, thus conditioning the camera for a second exposure. If the button is depressed for but an instant and then released, the locking disc |52 will hold the button depressed. by contacting the lower surface of the cam disc until the latter has completed one revol-ution, whereupon the spring |22 will snap the button |20 and plunger shaft I|0 outwardly to cause the locking disc |52 to re-enter the notch |50 and thus arrest rotation of the shutter disc 24. On the other hand, if the button |20 is held depressed bythe finger, the shutter disc 24 will continue to rotate, and exposures will be repeated at one second intervals until the button is released.

The aperture in the disc 24 is of such angular dimensions that one, and only one, exposure will be made during each' traverse of the aperture past the lenses.

In Figs. 8 and 9 there is illustrated a modified form of shutter release mechanism. In this modified form the sleeve |04 has a notched plate |00 mounted for rotation thereon, the notched plate being secured to th'e gear |00a, which is continuously driven by a pinion |20a. A plate |90a is rigidly secured to the sleeve |04 or formed integrally therewith. The-plate |00a has a. three armk lever |04 pivotally mounted thereon, one

arm |00 of this lever having a tooth for engagement with a notch' 01 of the notched plate |00.

The three arm lever |04 is normally urged to swing counterclockwise (Fig. 0) by a tension coil spring |00 which is tensioned between the end The end of the |04 in the position shown-in Fig. 8, with the spring |00 under tension.

When it is desired to make an exposure, the knob .|90 is pulled outwardly a sufficient distance to release the three arm lever |04 and permit it to swing counterclockwise under the influence of its spring |00. The toothed end of the lever arm |00 will then ride upon the edge of the disc |00 until the notchv |01 comes in alignment therewith, whereupon the tooth will fall into the notch and a positive driving connection will be formed between the notched disc |00 and the plate |02. The shutter disc 24 will thus be rotated through at least one revolution to make an exposure. If repeated exposures are desired, the knob |96 is held in its outward position so that the clutching mechanism remains engaged.

Whenever the knob |90 is released, the lever arm |99 will, in the course of its revolution, strike the end of the release bar |91 and thus disengage the toothed arm |00 from the notch |01. The parts will thus be returned to the position in which they are shown in Fig. 8, and will remain in this position until it is desired to make an additional exposure by again pulling out the release knob |90.

'Ihe mechanism shown in Figs. 8 and 9 constitutes a one-revolution clutch mechanism and may assume any one of a number of well known forms.

In utilizing the apparatus on' an aerial camera, the shutter release knobs |20, may be operated by means of a remotely controlled solenoid or the like, and exposures thus made at the will of the pilot in a fast low-flying single seat airplane. 'I'he exposure time may be made so short with the shutter mechanism of the invention that clear photographs may be made under such conditions.

In the foregoing description of the invention reference has been made to certain speeds and dimensions. It will be understood that such references are merely exemplary, and that the apparatus may be made in various sizes and the various parts arranged to operate4 at speeds. and

at speed ratios other than those specified. While I have shown and described particular embodiments of the invention, it will be apparent to those skilled in the art that the invention may be embodied in various forms, all utilizing the underlying principles of the invention. For example, the shutter discs may be arranged to rotate on different axes located in a cluster about the lens axis, instead of being coaxial as shown. I therefore desire, by the following claims, to include within the scope of my invention, all such modifications and variations by which substantially the results of my invention may be obtained through the use of substantially the same or equivalent means.

I claim: 1. In a camera shutter mechanism, the combination of a plurality of apertured discs including a shutter disc, means supporting said discs for rotation with their apertures capable o! registration with the lens opening of the camera, gearing for driving said discs at diiierent speeds such that their apertures will register with the lens opening of the camera only once during each revolution of the shutter disc, means normally holding said shutter disc stationary in a position in which it occludes the lens opening, and manually controllable means for releasing said shutter disc and operatively connecting it to said gearing.

2. The combination set forth in claim 1 in which means are provided to prevent release of said shutter disc except when the remaining-,discs are in predetermined positions.

3. The combination set forth in claim 1, in which a one revolution clutch mechanism is provided for operatively connecting said shutter disc to said gearing.

4. In a camera shutter mechanism, a plurality of adjacent opaque discs including a shutter disc, each disc having an aperture subtended by radii diverging at an acute angle from the centers of the discs, positive drive means for rotating said discs at different speeds such that the optical path I for light entering the camera will be cut on by one or several of said discs except when the shutter disc has its aperture in the optical path, means to rotate all of said discs except said shutter disc continuously, manually operated control means for establishing a driving connection between said drive means and the shutter disc, and means for disengaging said driving connection upon completion of one revolution of said shutter disc provided said manually operated control means has been released.

5. In a. shutter mechanism for cameras, the combination of a`plurality of apertured discs including a shutter disc, said discs being mounted for rotation in a position such that their apertures may register with the lens opening of a camera, gearing driving said discs at different speeds and in predetermined phase relation, with the shutter disc driven at lowest speed, means normally holding said shutter disc stationary withy its aperture not registering with the lens opening, and manually controllable means for effecting an operating connection between said gearing and said normally stationary shutter disc to cause the latter to rotate through one revolution in a predetermined phase relation with respect to the other discs.

6. In a. shutter mechanism for cameras, the combination of a plurality of opaque discs including a shutter disc, each of said discs having a transparent portion forming an aperture for the Y camera, driving means for rotating said discs at different speeds and in such phase relation that their apertures will register with the lens Opening of the camera only once during the traverse of the aperture of the shutter disc past the lens opening ci the camera, said shutter disc rotating at the lowest speed, stop means normally holding said shutter disc stationary in a position in which its aperture is not in registry with the camera lens, and a manually controllable one revolution clutch mechanism including means for rendering said stop means ineilective and connecting said normally stationary shutter disc to said driving means to cause the shutter disc to rotate through one revolution.

7. In a camera shutter mechanism, the combination of ve discs including a shutter disc, each disc having an aperture capable of registration with the lens of the camera, motor means and gearing for driving said shutter disc intermittently and the remaining discs continuously, said gearing being operable to rotate said discs at different speeds in predetermined phase relation, with the shutter disc rotating at the lowest speed, a manual control element, means associated with said element normally to hold said shutter disc stationary and eitective upon operation of said manual control element to release said shutter disc, and one revolution clutch mechanism controlled by said manual control element and said last named means for rotating said shutter disc through a single revolution in a predetermined phase relationship with respect tb the other discs.

LAURENB HAMMOND. 

